Pages

Tuesday, October 28, 2014

I received an announcement for a panel discussion on "Urbanism, Patrimony, Ownership, and Culture in Florida" to be held at:

Wolson Campus of Miami Dade College

300 NE 2nd Ave., Room 7128,

First Floor of Building 7

on Thursday, November 6th

at 6:30 pm

Free and Open to the Public

Here's the poster.

The announcement I received says it is a "panel on the current archaeological excavations at Met
Square (which include a prehistoric village, Ft. Dallas, and the historic Royal
Palm Hotel). This panel will include the County Archaeologist Jeff Ransom, the
UM Archaeologist who has an ongoinglegal battle with the City in an attempt to save the site, Dr. Will
Pestle, Mary Lou Pfeiffer from FIU who wrote a book about the legal aspects of
the handling of the famous Miami Circle, and an Urbanism Professor from UM, Dr.
Allan Shulman.

"This panel is supported by a grant from the state of
Florida and news alerts have been sent to all local South Florida museums,
universities, and news organizations including the Miami Herald and NPR."

Friday, October 24, 2014

An article has come out in Current Biology in which the authors report the sequencing of over 650,000 SNPs (single nucleotide polymorphisms) from 27 Rapa Nui individuals. I don't have access to the full article, but I've read the abstract and a discussion of it from today's issue of Science (Lawler, Andrew, 2014, Epic pre-Columbian Voyage Suggested by Genes, Science Vol. 346, No. 6208, p. 406). Native American DNA composed about 8% of the Rapanui genome. They explain this by invoking pre-Columbian trans-Pacific journeys from Easter Island to the Americas and back. They argue that the introgression took place in pre-Columbian times, rather than in recent or historical times, because the Native American DNA segments are fragmented and scattered. The degree of fragmentation and dislocation allow the authors to infer a date of AD 1280–1495 for the contact.

Of course, these issues--Easter Island and trans-Pacific contact--are popular and therefore controversial questions. So, naturally some Norwegians have to defend Thor Heyerdahl by saying that this means that the South Americans sailed to Easter Island. Right. And just happened to get there at the same time as the Polynesians. Sure. That's more likely than the Polynesians, who'd been sailing around the Pacific for thousands of years and who had developed unique maritime technology and navigational knowledge, sailing to South America. Nothing against the South Americans, but dude, this was the Polynesians' thing. In fact, it's hard to imagine that the Polynesians, who, over a period of two or three thousand years, had found and settled virtually all the tiny Polynesian islands, would suddenly stop at Hawaii and Easter Island. Right. You sail all over the Pacific for millennia and find all the little islands, but miss the giant continent in front of you. Yeah, that's really likely.

Of course, the South Americans did have boats and sailed around some, but there's little evidence that they crossed the open ocean to Polynesia. Sure, a boat might have drifted there, as they occasionally do today, but that's not really in the same league.

Added to the pre-Columbian chicken bones from Chile with (possibly) Polynesian chicken DNA in them and the evidence that the yam diffused to Polynesia from South America, and the evidence for pre-Columbian trans-Pacific contact is getting stronger.

I accidentally added a misspelled word to my word processor's custom dictionary, so I had to edit it, which required a long, convoluted, painful web search for instructions. But once I had it open, I reviewed it and found all kinds of weird stuff in it. Here are the interesting ones:

Svante Pääbo's team has produced the earliest Homo sapiens genome so far, extracted from a directly radiocarbon-dated femur found in western Siberia. Two AMS dates on the collagen combined to produce a calibrated date of 46,880-43,210 cal BP. Stable C and N isotope analyses indicate a diet based on C3 plants and animals that ate them. The bone is from a male whose mtDNA falls near the root of the R haplogroup, which is widespread in modern Europe and Asia. The Y chromosome is similarly ancestral a widespread Eurasian haplogroup. They called the specimen "Ust'-Ishim" after the location in which it was recovered.

The authors find that the individual was probably related to or
derived from an early population involved in the dispersal of modern
humans out of Africa. Principal components analyses (PCAs) of the autosomal DNA suggest this guy was more closely related to non-Africans than Africans. In fact, when comparing the autosomal DNA only to modern non-Africans the authors observe that the specimen falls near the origin of the graph (of the first two components) and interpret that to indicate that he was equally-closely related to all modern non-Africans.

There may, however, be a better interpretation. In both PCA plots the Ust'-Ishim genome fell closest to modern Central and South Asians, which would make sense too, given the location of the find. I haven't read the Supplementary materials yet (they're 115 pages long), but I did review Section 10, which addresses this issue. To my mind, the results of the admixture analysis shown in Supplementary Figure S10.3 do indeed suggest that the Ust'-Ishim genome is closest to Central Asians, such as the Pathan, Sindhi, Burusho, Hazara, and Uygur. (The ethnic labels come from the article.) These are all central Asian peoples from Pakistan, Afghanistan, and western China. The match between the bars representing those peoples and the Ust'-Ishim genome is not perfect (the former are missing a purple patch and a bit of dark blue that appear in the ancient genome), but to me that match it does seem markedly more similar than the others. Unfortunately, the subsequent phylogenetic analyses do not address this question as they do not include central Asian genomes. So, I'm not sure I agree with the authors' interpretation that this new specimen is equally related to all Eurasians. If the Ust'-Ishim individual is more closely related to central Asians than to others, it implies a remarkable degree of geographic stability. This is an obvious hypothesis that probably should have been addressed. I hope it is investigated in the future.

They also found a 2.3 +/- 0.3% Neanderthal admixture, showing that their inter-species cuddling had already taken place by 45,000 BP. Curiously, given the date and location, there was no Denisovan admixture. The percentage of Neanderthal admixture is a bit higher than in modern humans, but not by much. As one would expect, the characteristic length of the Neanderthal DNA segments is substantially greater (~1.8-4.2 x) in the Ust'-Ishim genome than in modern ones, because the fragments were subsequently broken up further by recombination. Actually, this fragmentation process can provide an estimate of the length of time since the admixture took place, which the authors estimate as 232-430 generations earlier, or 50,000-60,000 BP, using a 29-year generation length. This corresponds approximately to some estimates of the time of expansion of modern humans out of Africa, but post-dates the putatively early modern humans from Skhul and Qafzeh. Some longer Neanderthal segments in the Ust'-Ishim genome imply that later admixture events also occurred. Interestingly, Figure 5 in the article illustrates homozygous versus heterozygous Neanderthal-derived alleles in the Ust'-Ishim genome compared to several modern ones. The Neanderthal alleles in the ancient genome are all heterozygous whereas some of the modern ones are homozygous. This makes sense, as one would expect by chance alone (panmixia) that heterozygous derived alleles would be more common earlier in the gene flow process. Probabilistically, it would take time for homozygosity to develop. Figure 5 only shows Chromosome 12, but it is suggestive.

Because the specimen is directly dated, it could be used (along with other specimens) to help calibrate the "genetic clock" that calculates age of genetic divergence from mutation rates, and the authors did so. The new estimates of mutation rates in autosomal DNA from this study are lower (slower) than some, possibly implying a longer time interval since the split from archaic human relatives.They also provided new Y Chromosome and mtDNA mutation rate estimates.

Finally, it is noteworthy that the authors find that the Ust'Ishim individual was not more closely related to the Andaman Islanders than he was to modern East Asians or Native Americans. I say this is noteworthy because some documentaries have made, in my opinion, far too much of the Andaman Islanders' genes as evidence for a coastal, southern migration route for early modern humans.

Okay, so they recorded high resolution bathymetry of the continental shelf along the Carolinas and Florida coast. They noticed these big furrows that they apparently can attribute to the keels of icebergs dragging through the sediments. Then they ran ocean circulation simulations that showed that big meltwater discharges from Hudson Bay or the St. Lawrence during the last deglaciation could have pushed icebergs as far south as the tip of Florida, although they would have been more common further north, along the Carolina coast. These kinds of events ought to have provided bursts of cold fresh water. I wonder if signals from those events could have been recorded in coral or shellfish.

Wednesday, October 8, 2014

I recently read The Archaeologist Was a Spy by Charles H. Harris III and Louis R. Sadler (Albuquerque: University of New Mexico Press, 2003). It's a detailed exposition and discussion of Sylvanus Morley's espionage work during World War I. I think I knew previously that he was one of those denounced for spying by Franz Boas in his famous letter to The Nation after the war. But I did not know how central the role that he played was in not only in the spying itself but also in setting up the entire network of spies. I also knew nothing about the object of the espionage or its significance. As it turns out, the historians who wrote the book showed that Morley played a pivotal role in identifying and recruiting others, particularly archaeologists, into the network, which was run out the Office of Naval Intelligence. In those years, German U-boats threatened not only United States shipping and even our ports and coastal towns, but also the vital military links between the US and its European allies. The possibility that German U-boats could refuel and re-arm in nearby waters was a grave concern because it would have multiplied their effectiveness. Morley's primary task was to survey the Atlantic coast of Mexico and Central America to determine where it was physically--bathymetrically--possible for the U-boats to put in to ports, bays or inlets (preferably undetected) and resupply themselves. He was also on the lookout for German activities ashore that might indicate the willingness or ability to assist such a mission. I was surprised to learn that he was one of the dominant actors in such a key drama.

A couple of warnings. First, there is exceedingly little archaeology in the book. It's not a biography of Morley as much as it is a history of American espionage. Second, toward the end, the authors celebrate Boas's censure, and by implication the vindication of their protagonists, by the American Anthropological Association. But it's not clear to me what they are really saying. That American scientists ought to spy using their profession as a cover? That it's patriotic to do so? That we can do so with a clear conscience because we can assume that foreign scientists (or perhaps American ones) are spying on us? What about the argument that spying by some puts us all under suspicion? This not just theoretical for me. I have worked in countries that are not America's best friends, and who therefore would reasonably be on the lookout for American spies. Not only am I an archaeologist, but I worked for the Navy for a time. Worst of all I went to Yale, the great hothouse in which American has long propagated her budding spies. None of that means that I'm a spy, and in fact I'm not, but I don't want to have convince an interrogator of that.